By now, the American people surely appreciate the fact that the costly days of President George W. Bush and his principal advisers, Dick Cheney and Donald Rumsfeld, are behind them, that no longer is it America’s impulse to send in the troops whenever a crisis erupts overseas.

But echoes of that unfortunate period in modern American history are still being heard as doctrinaire conservatives train their sights on President Obama’s reluctance to go head-to-head, militarily, with Vladimir Putin over Russia’s behavior in Ukraine.

“We have a weak and indecisive president that invites aggression,” U.S. Sen. Lindsay Graham, of South Carolina, declared the other day. “President Obama needs to do something.”

Joining Graham’s criticism of Obama was the president’s rival in the 2008 election, Sen. John McCain, of Arizona, who said that “nobody believes in America’s strength anymore.”

McCain and Graham have been a partisan political pair for some time now, and it seems their common bond is a deep reservoir of contempt for this president. If the American people have grown tired of their act, the senators have only themselves to blame.

But it appears that nearly all conservative commentary — led by the editorial page of The Wall Street Journal and the one-note harping by the pundits on Fox News — would love to see the White House emulate the Bush-Cheney-Rumsfeld approach to foreign affairs and once again put American lives needlessly at risk.

Americans need to understand this: As offensive and abrasive as Putin may be (and few would argue he’s not deserving of our contempt), there is no plausible reason for our country to mount a military response to Russia’s behavior in Ukraine and especially its virtual invasion of Crimea.

Does anyone (outside the conservative community, that is) truly believe that Putin acted only because he regarded Obama as indecisive? If so, how then do they explain similar events in history, including the Soviet Union’s invasions of Hungary in 1956 or Czechoslovakia in the 1960s?

Are these critics of a supposedly weak Obama prepared to suggest that President Dwight Eisenhower, a Republican, was woefully indecisive and that’s why Moscow acted so brutally against Hungary? Would they argue that President Lyndon Johnson, he of Vietnam fame (or notoriety), was so weak that Czechoslovakia was vulnerable to Moscow’s ruthless predations?

It’s not that there aren’t valid arguments about Obama’s foreign policy. For example, many Americans are relieved that he’s finally planning a full withdrawal from Afghanistan, although others fret that leaving too soon could very well result in a revival of the Taliban. But that debate is honorable and legitimate.

There’s also reason to honorably question the president’s policies toward the civil war in Syria, although it’s difficult to see how he could have done more — especially from a military standpoint — as long as Russia and China were poised to veto any steps taken by the U.N. Security Council.

We suspect that most Americans — or at least those who haven’t embraced a partisan political agenda — are pleased that Washington has taken a more thoughtful and analytical approach to the challenges that arise from time to time in other nations.

International experts propose economic sanctions rather than bombs and bullets to impede Russia’s ambitions while assuring the new Ukrainian government that the European Union and the United States stand ready to provide substantial financial assistance.

Yes, Crimea may be lost by Ukraine, but remember that for a long time it was a part of Russia and a majority of its people speak Russian and want to be Russian.